Electric furnace.



PATENIAED JUNE 4, 1907.

A. 0, HIGGINS.

ELECTRIC EURNACE.

APPLICATION FILED APR. 6

2 SHEETS-SHEET 1.

PATENTED JUNE 4, 1907.

A. G. Hmmm, ELECTRIC FURNAGE. APILIQATION FILED APE.6,190G.

2 SHEETS-SHEET 2.

ALDUS C. HIGGINS, ()F WORCESTER, ALXHSACIllSET'lS.

ELECTRIC FURNACE.

Specification of Letters Patent.

Patented June 4, 1907.

Application tiled April 5,1906. Serial No. 310.359.

Be it known that I, Amn's C. ll'rculxs, a citizen of thc Inited States, residing at IVoicestcr, in the county of vWorcester and State of Massachusetts, have invented certain new and useful Improvements in Electric Furnaces, of which the following is a specification.

The object of the present invention is to provide an electric furnace of relatively large capacity and so constructed as to permit the product to be formed and subsequently cooled under more nearly uniform temperature conditions than has heretofore been possible, and at a rate within the control of the operator. Aln its referred form the furnace is designed to facilitate the discharge or removal of the product, and the walls are effectively'protected against injury due to the high internal temperature.

For a full understanding of my invention reference is made to the accompanying drawings wherein:

Figure 1 is a central vertical section, online 11 of Fig. 2, of' one form of furnace constructed in accordance with my invention. Fig. 2 is a horizontal section on line 2-2 of Fig. 1. Fig. 3 is a side elevation of a moditied form. Fig. 4 is a horizontal section on line 1"4 of Fig. 3. Fig. 5 is a central vertical section of a further modification. is a horizontal sectimion line (5 6 of Fig. 5, and Fig. 7 is al horic/.ontal section of another modification.

The type of furnace shown in Figs. 1, 2, 3,

'4 and 7 com rises a movable hearth 1 having a lefractory )ed or lining 2, preferably of carbon, surrounded by a metallic trough or basering 3 which serves to collect the water used for cooling the furnace walls or chilling the roduct as hereafter described. The shell or `urnace casing 4 may be constructed of boiler latel or sheet-iron, and is separable from the iiearth, lugs 5 being provided for lifting it therefrom. The shell is preferably inwardly inclined toward its `upper end as shown. Cooling of the furnace walls, and through them of ad'acent portions of the product, is effected by water su )plied through perforated pipcs (i surrounding the upper portion of the shell and supported thereon by lugs 7; the pcrforations in pipe 6 are arranged to di.w rect the water against the shell t in such mannerthat it llows down the inclined sul'- face thereof in an unconined stream or lilith, substantially as described in my prior patl ent, No. 775,654, patented November 22, 1904, to be collected by the base-ring 3 and discharged through a suitable waste. pipe S. The furnace. is shown as having stationary electrodes depending into the casing in position to heat the charge or material therein either by arc or incandescence; the crucible is adapted to be gradually lowered during the operation, as for instance. by means of a direct plunger hydraulic elevator the plunger of which is shown at 10.

in electric furnace operations it is frefluently desirable that overheating of the product should be avoided, and also that the product should be cooled or chilled at a delinite rate within the control of thc operator. As one example. of an operation of this character l may mention the production of an 'abrasive by the fusion of an aluminous `material into a pig or mass, as more fully set forth in my copendin-g application, Serial No. 307,090, filed March 2o, 190e. The

pendent upon the rate at which the fused material is cooled, and it is obvious that in a furnace of large diameter the rate of cooling of a given portion of the product through external walls will depend upon the distance of such portion from the walls; and that owing to this fact the final product will vary considerably in character in accordance with such distance. In my construction suchr dill'ercnccs are minimized, and by properly proportioniug the furnace in accordance with the character'of the product, material which is sulliciently uniform for commercial purposes is readily obtained.

- The essential feature of my construction is the production of a furnace which is of such form that while a large capacity is irovided, all portions of thc charge are brougiit wit-hin the cooling influence of cooled walls, in such manner as to secure commercial uniformit of the product. To this end I provide a rela tively long and narrow furnace chamber and means for cooling the walls of the chamber. The expression relatively long aml narrowas herein employed is not inten-ded te indicate that the chamber must necessarily be substantially rectilinear but is intended to include annular or equivalent constructions.

chamber ol' this character and ofgrcat capacity is formed by providing within a substantially rectangular chamber a central wcll 11, having inclined wallsv 12, constituting the character of the product in this case is dc-` Figs. 1 and .2 show a furnace,wherein a 

